VFC Scar-L Feeding issues

Trying to get a Scar L with an F2 and Maxx hopup up and running but having a weird issue. When assembled, there is no feeding whatsoever. I’ve tried using the stock hopup, different FCU settings, mags, etc and can’t get anything. When I take the upper off and push the inner barrel assembly against the GB and shoot it works great. Looking into the gun when assembled it seems like everything is good. Anyone have any ideas for a fix?